Prostate cancer is the most common cancer in men over age 50. It is the cause of the most cancer deaths after lung cancer. One man in 10 in the United States will develop prostrate cancer, and perhaps one in 30 will die from it. Often there are no symptoms in the early stages.
The prostate is a cluster of small glands found at the base of the bladder in men. Cancerous cells can grow in this gland. Most prostate cancers are discovered during a routine physical exam. If they are not discovered early and are allowed to grow, they can make urination uncomfortable. Some prostate cancers spread, while others never do. If they spread, they can cause pain in the lower back or pelvis. Prostate cancer that spreads into the bones, bladder, or other organs can be fatal.
Every year an estimated 200,000 new cases of prostate cancer are diagnosed, and about 38,000 men die of it. The causes of this disease are not fully understood.
Risk factors include:
- aging (98% of cases are diagnosed in men over 55)
- family history of prostate cancer
- ethnicity (African-American men are at higher risk)
- eating a high-fat diet
- occupation (welders, battery manufacturers, rubber workers, and those exposed to cadmium are at higher risk)
As men age, the prostate enlarges. As it grows, it may develop growths or nodules. Most of the time these growths are normal tissue; in this case, the condition is called benign prostatic hypertrophy (BPH). When the growth is cancerous, the cancer cells are often so small and grow so slowly that they are not life-threatening. If the cancer tumors do reach a certain size, they can spread from the prostate to bones or other organs. In such cases the cancer can be fatal.
The most common way to screen for prostate cancer is through a rectal exam. The doctor sticks a gloved finger inside the rectum and feels for any abnormalities in the prostate. By itself, this method is not always reliable. Two-thirds of the growths found in this way are not cancerous, while quite a few cancers may go undetected.
The prostate-specific antigen test (PSA) is a blood test that has made diagnosis easier. This test measures a protein produced in the prostate that may increase when cancer is present. However, not all cancers cause this protein to increase, so a negative PSA test does not necessarily mean the patient is cancer-free. On the other hand, a positive PSA test may also be a false alarm. When the PSA blood test is combined with a rectal exam, it increases the chance of detecting prostate cancer by one-third.
If prostate cancer is suspected, a specialist (urologist or oncologist) may perform a biopsy on the prostate. A small sample of the prostate tissue will be removed to determine whether or not it is cancerous.
If the biopsy shows that a patient has prostate cancer, other organs, such as the kidneys and bladder, may need to be examined by X-ray or ultrasound. The doctor may also look inside the bladder with a viewing tube (cystoscope) to see if any cancer has spread, or use a CT scan to see if the cancer has spread into the bones.
Doctors are looking for ways to determine which cancers will spread and which will stay within the prostate. Testing for one protein called KAl-1 seems to be a reliable indication of the likelihood of the cancer spreading.